THE THEORETICAL STATUS OF $\bar{B} - B$-MIXING AND LIFETIMES OF HEAVY HADRONS

Abstract

In this talk we review the theoretical status of the lifetime ratios of heavy hadrons and of the B-mixing quantities ΔMs, ΔΓs and φs. While ΔMs and ΔΓs suffer from large uncertainties due to the badly known decay constants, the ratio ΔΓs/ΔMs can be determined with almost no non-perturbative uncertainties, therefore it can be used to look for possible new physics effects.